Food composition is the detailed breakdown of the nutrients and other components present in a particular food, usually expressed per 100 grams or per typical serving. It covers macronutrients — protein, fat, and carbohydrate — along with fibre, vitamins, minerals, water, and often energy value, and may extend to fatty acid profiles, amino acids, and phytochemicals. Composition data underpin nutrition labelling, diet planning, epidemiological research, and food product development. National databases such as the UK’s Composition of Foods and the USDA nutrient database compile analysed values for thousands of foods, though natural variation means figures are representative rather than exact. Analysts determine composition using standardised laboratory methods for proximate analysis, vitamins, and minerals.